Ventoy MBR & GPT

• Ventoy MBR vs GPT

• Is there any difference in Ventoy's function between MBR and GPT ?

No. For Ventoy there is no difference between MBR and GPT.

• Does MBR support Legacy BIOS and UEFI ?

Yes. But there are some machines whose UEFI firmware only recognize disk in GPT format, so MBR will NOT be compatible in this case.

• Does GPT support Legacy BIOS and UEFI ?

Yes. GPT is part of the UEFI spec, so GPT supports UEFI without any compatibility issues.
But for Legacy BIOS, there may be some compatibility problems with some machine, that's why I give 3 stars here, see Notes
To be exactly, the active flag can't be set in GPT's protect MBR. Besides the partition type (0xEE) is not accepted by some BIOS.

• Which style should I select? MBR or UEFI?

Anyway, the best for you is the best